Shenmue........ without question or hesitation...!!!!!!

on the list only.........
2. Virtua fighter 3.
3. Virtua striker 2.

Not on the list but a distant second to Shenmue...... Virtua tennis.

Ah yes, Sega's swansong in the console market. If only things had turned out differently for the Saturn, they may still be in the market today.
Being the Sonic fan that I am, of course I'm going to say Sonic Adventure is my favorite of the listed games (With that said, I prefer Adventure 2.)
Being in the Generation of Remakes, as I like to call it, it would be amazing to see some of this system's beloved classics get remade for modern consoles. (Where are my Sonic Adventure 1 & 2 Remakes, Sonic Team?!?)

SEGAGAGA - though I really wished I'd understand Japanese, both now and back then

For me it is Veronica. It was really an eerie game at the time and the visuals and athmosphere were top notch.

Shenmue II is my favourite, but that's not on the list, so Shenmue 1. I have some fond memories of the Dreamcast, it's still the my personal favourite console design. Seeing it in person, it looks just right. Sonic, Soul Calibur, Skies of Arcadia, Metropolis Street Racer, Chu Chu Rocket and DOA2 were some of my other favourites. It's also the only system to have POD 2, not a great game, but one that I'm fond of (as well as the first POD on PC).

The controller had a nice idea with the VMU, but overall it was a worse controller than the Dual Shock, and only a small improvement over the Saturn "3D Control Pad". It was also slow to load and noisy (compared to other consoles) but it was pretty ambitious. It had quite a good library for such a short lived system.

Phantasy Star Online

SoulCalibur made me not want a PS2, which I never got, so I have to give credit to that game. It's probably the best fighting ever made, and we played a lot of multiplayer. Besides that there's Crazy Taxi, played it a lot, great for short sessions.

Power Stone 2 and Bomberman Online were the most played at my home

^This guy.  Closing in on 12 years registered, makes his first post.

Alien Front Online is probably my #1 DC game. From the best selling list, Soul Calibur. Crazy Taxi a close second. Virtua Tennis isn't on the best seller list either, but right up there as an all time fav.

Out of the poll choices, Seaman, but it's actually a pretty tough call between Seaman, Jet Grind Radio, and Space Channel 5 for me.

There were so many really creative games for the Dreamcast!